US regulators voted Thursday to roll back so-called "net neutrality" rules that require internet providers to treat all traffic equally, amid an acrimonious debate over how it impacts online freedom.

The Federal Communications Commission, in a 3-2 vote, adopted a proposal by Republican appointed chairman Ajit Pai, who said his plan would end "heavy-handed" rules which discourage investment and innovation.

Democratic member Mignon Clyburn, one of the two dissenters, said the agency "is handing the keys to the internet" to "a handful of multi-billion dollar corporations."

The vote followed a heated partisan debate and is just the latest in a battle over more than a decade on rules governing internet service providers in the courts and the FCC.

Net neutrality activists have staged a series of protests in cities around the US and online, amid fears that dominant broadband providers could change how the internet works by favoring its own services and hindering those of rivals.

Pai said ahead of the vote that his plan would restore "light-touch" rules which allowed the internet to flourish, and promote investments to enable new and emerging services.

"The digital world bears no resemblance to a water pipe or electric line or sewer," Pai said.

"Entrepreneurs and innovators guided the internet far better than the heavy hand of government."

But dissenting FCC commissioner Jessica Rosenworcel said the rollback will hurt consumers and others.

"Net neutrality is internet freedom. I support that freedom," she said.

"This decision puts the Federal Communications Commission on the wrong side of history, the wrong side of the law, and the wrong side of the American public."